Incandescent electric lamp and process of producing the same



June 11, 1929.- A. L. BECKET INGANDESCENT ELECTRIC LAMP AND PROCESS OFPRODUCING THE SAME 2 Sheets-Sheet 1 Filed Nov. 11, 1925 INVENTOR.

A TTORNEYS June 1929. A. L. BECKET INCANDESGENT ELEC'iRIC LAMP ANDPROCESS OF PRODUCING THE SAME 2 Sheets-Sheet 2 lfga flgfd 1271.

fl M IYNVENTOR.

- ATTORNEYS Patented June 11, 1929.

UNITED STATES ALAN L. BECKET, 0! EAST ORANGE, NEW JERSEY 1,716,912PATENT OFFICE.

IN CANDESCENT ELECTRIC LAMP AND PROCESS OI! PRODUCING THE SAME.

Application filed November Heretofore in the manufacture of incandescentlamps, the lead-in wires have been sealed in fused glass, the wiresbeing made of metals having substantially the same coeflicient ofexpansion as the glass itself to prevent rupture of the glass or leakagealongside the wires. In prior practice, the leads are installed somewhatclose together so that it becomes necessary, especially with gas filledlamps of high candle power, to dispose the filament a considerabledistance from the point where the lead-in wires are sealed in the glassto prevent the material between the wires from becoming overheated andcausing arcing between the leads. A micadisc is sometimes installedbetween the filament and the sealed lead-in wires to reflect the heatand avoid arcing, sary to provide a bulb of so as to obtain the properdistance between the filament and,the point where the lead-in wires aresealed. Another disadvantage that occurs with electric, lamps is thatthe cementitious material that attaches the metal base to the glass neckalso sometimes becomes overheated from the filament and is ruined.Another disadvantage is that for manufacturing reasons it is necessaryto use lead-in wires of limited shapes because of the pressure whichmustbe applied to the glass to form the seal. For instance, a thin ribbonlead-in Wire cannot be' easily manipulated.

Bythe present invention, the above difliculties can be largely overcome,and other advantages that Will be understood as the description proceedswill be obtained. With this invention the filament can be installed nearthe point where the lead-in wires are sealed in the glass without dangerof arcing, thus enabling a shorter bulb and bulbs of a greater varietyof shapes to be used. The cementing material between the metal base andthe neck 'of the bulb is protected from excessive temperatures when ametal base is used, thus decreasing the tendency of the same to becomeoverheated. The bulbs may be made of such shape that the blackening isnot so objectionable, or canbe segregated in portions where it will dothe least harm and, at the same time, portions of the bulb may be coatedto give better reflection of the light.

The invention will be understood from the description in connection withthe accompanying drawings in which Figs. 1 to 5 show vertical sectionsthrough the neck of an inb and even then it becomes neces considerablelength 11, 1925. Serial No. 68,267.

candescent light bulb, in which successive stages of the installation ofthe lead-in wires are shown lamp, partly in section, and Figs. 7 to 11inclusive illustrate different shapes of lead-in wires; Figs. 12, 13 and14 are sectional views illustrating a modification.

In the drawings, reference character 1 indicates the cylindrical neck ofan incandescent light bulb, the bulb itself not being shown, in whichthe lead-in wires 2 are shown hanging inside the neck portion with thefilament 3 attached to the lower ends thereof, the upper ends being bentoutwardly over the top edge of the neck. A glass blow pipe is shown at4, with a molten mass of glass 5 at the lower end thereof in Fig. 1.Fig. 2 shows the glass blow pipe 4 lowered, and also shows the glass 5after it has begun to be blown into a somewhat spherical shape. Fig. 3shows further progress of blowing the glass until its outer surface haspressed against the wires 2 and enveloped the same. It will beunderstood that the neck portion 1- will also be simultaneously heatedto the fusing temperature, -so that the glass of the portion 5 will fusetherewith, thus causing the lead-in wires 2 to become sealed in place.Fig. 3 also-shows the progress of blowing the glass to the point wherethe bubble'bursts, leaving a hole at the lower portion, as shown at 6.After the bubble bursts, the glass blow pipe 4 is drawn outwardly, thusdrawing a tube, as shown at 7 in Fig. 4. This tube is used forexhausting the air from the bulb, and also in case gas filled lamps areused, it may be used for introducing the gas intothe bulb after the airhas been exhausted. After exhaustion of the air and introduction of thegas, the tube 7 is sealed by fusing the same near the upper end of theglass 5, thus leaving the same as indicated at'8 in Fig.5. The lead-inwires may have attached thereto an insulating or arcing support 10 (Fig.6), from which a filament anchor 11 may extend to the filament 3 tosupport the same.

After the lead-in wireshave been sealed to the neck of the bulb, asabove described, the screw-threaded metal lamp base 13 may be attached,one of the lead-in wires being connected thereto, as shown at 14, andthe other one being connected to the central middle contact 15, in theusual manner, the cementing material 16 being used to connect the ase tothe neck. In case it is not desired to F 6 shows the complete electricuse a metal base on the neck of the bulb, the

neck itself can be made to serve as the screw plug. This is shown mostclearly in Figs. 12', 13 and 14. In Fig. 12 the neck 1 is shown.surrounded by an internally threaded mold 30, while the glass bubble isbeing expanded against theinside walls of the neck to seal thelead-inwires 2 in place. At the same time, the glass of the neck 1 isforced outwardly into the threads of the mold, as shown in Fig. 13, thusleaving a threaded glass neck when the mold is removed. The end of oneof the lead-in wires is caused to be exposed a socket so as to hide thesocket almost entirely. This is possible because the lead-in wires aresufficiently far apart to avoid danger of arcing,'even when the filamentis installed close to the point where the lead-in wires are sealed.Besides, the lower end 5' of the glass that was used for sealin in thewires and the chamber in the glass bu ble aid in shielding both thelead-in wires and the cementitiousmaterial from the heat of thefilament. With a bulb made inthe shape indicated, in Fig. 6, a largeportion of the depositfrom the filament will collect along the annularportion 20, so that there will not be a dense black backgroundimmediately. be-

hind the filament to cause glare. Also the top portion of the lamp canbe coated, as shown at 19, with material which will cause the light tobe reflected downwardly and distributed more satisfactorily.

Instead of using ordinary round lead-inwires lead-in wires of a varietyof shapes' may be used with this invention. For example,-Fig. 7indicates a lead-in wire that 1 has a-flat ortion 21 to be sealed in theneck of the bul Fig. 8 represents a lead-in wire in the shape of aribbon 22 that is corrugated, Fig; 9 shows one in which the ribbon 23 istwisted, Fig. 10' shows a round wire that is corrugated as shown at 24,and Fig. 11 shows a coiled lead-in wire 25. These and other forms oflead-in wires ma be used, as .the sealing in bubble of fused g ass willwet the lead-in wires and cause the same to become hermetically sealedalong the inside of the neck portion of the" lass bulb. The leadin wirescan be installe in all cases by merelyl hangin the same in the neckportion, as s own in 1g. 1, and expandin the molten glass against thesame from the inside, while through glass.

the glass of the neck portion of the bulb is also in a fused orsemi-plastic state, so that no manipulation of the lead-in wiresthemselves is required during the time they are being sealed in theglass. The outward pressure of the expanding glass presses the wiresinto place and enables them to become embedded in the glass. Thepressure from the expanding glassbubble is not excessive so that acoiled, hollow or flat lead-in wire, or one of other shapes, can be usedand it will retain its shape while being sealed in place in this'mannerfThe use of certain shapes of lead-in wires is impracticable in thepresent day incandescent lamp manufacture, due

to the fact that the pressing or squeezing to produce the seal intheglass would distort the shape of the lead-in wire.

The bubble seal offers decided advantage for lamps designed to burn morethan one filament. Such lamps often use more than two lead wires whichare extremely difficult to arrange in the ordinary squeezed tubing seal.The bubble seal-provides ample room for a large number of leads andavoids the complications involved in the tubing seal.

It is to be understood that this invention is not only applicable toincandescentlamp manufacture, but also to the manufacture of radio"tubes, are lamps and the like, in which lead-imwires are to behermetically sealed With a bulb shaped as indicated in Fig. 6, thereflector 19 does not focus the'heat rays upon the filament or causecrossreflections between the walls of the bulb, but has the effect ofdistributing the rays. The lamp is very compact and because of its shortaxial.

length, the filament is less apt to vibrate when the lamp is usedin'trains or the like, where vibration is excessive. Also, due to thecompactness of this lamp, it can be packed for shipping in much smallerspace than the usual lamp and with less liability of breakage.

' In manufacturing this lamp there will be a material saving in scrapand breakage since the operation of sealing the usual filament mount tothe neck of the bulb is entirely I eliminated on account of doing away.wit the filament mount itself. The fact that ribbon lead-in wires andother shapes may be usedmakes it possible to manufacture a lamp withoutthe complicated dumet wire, which is a combination of different metalsand expensive to manufacture.

I claim: a

1. The process of manufacturing an incandescent lamp which comprisesintroducing lead-in wires into the neck of the lamp bulb, introducinmolten glass between the wires and expan ing it a ainst the same.

2. The proces'sro manufacturing an irican descent lamp which comprisesintroducing lead-in wires into the neck of the'lamp bulb,

introducing molten glass between the wires and expanding a thin layer ofthe glass against the same.

3. The process of manufacturing an incandescent lamp which comprisesintroducing lead-in wires into the neck of the lamp bulb and blowing abubble of glass against the same until it bursts.

4. The process of manufacturing an incandescent lamp which comprisesintroducin lead-in wires into the neck of the lamp bulb, introducingmolten glass between the wires and expanding the glass against the wireswhile keeping said neck heated.

5. The process of manufacturing an incandescent lamp which comprisesintroducing lead-in wires into the neck of the lamp bulb, blowing abubble of glass against the same until it bursts, and drawing a portionof said bubble into artube.

6. The process of manufacturing an incandescent lamp which comprisesintroducing lead-in wires into the neck of the lamp bulb, blowing abubble of glass against the same until it bursts, drawing a portion ofsaid bubble into a tube, and using said tube for ex hausting the airfrom said lamp bulb.

7. The process of manufacturing an incan descent lamp which comprisesintroducing lead-in wires into the neck of the lamp bulb, blowing abubble of glass against the same until it bursts, drawing a portion ofsaid bubble into a tube, and using said tube for exg hausting the airfrom and introducing gas into said lamp bulb.

8. The process of manufacturing an incandescent lamp which comprisesintroducing lead-in wires into the neck of the lamp bulb, blowing abubble of glass against the same until it bursts, and sealing saidbubble by fusion.

9. The process of manufacturing an incandescent lamp which comprisesintroducing lead-in wires into the neck of the lamp bulb, introducingmolten glass between the wires,

expanding molten glass against the wires, and 45 providing screw threadson the neck.

ALAN L. BECKET.

